D-Tartaric acid → (R)-3-(2-ethoxyphenoxy)piperidine D-tartrate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A slurry of 3-(2-ethoxyphenoxy)piperidine hydrochloride (200 g, 0.776 mol) and D-tartaric acid (118 g, 776 mol) in acetone (3.0 L) was warmed to 56° C. and was held at that temperature for 2 hours. The mixture was cooled to 20° C. and was held at that temperature overnight. The crystals were collected by filtration, rinsing with acetone (1 L), and then were dried to afford (R)-3-(2-ethoxyphenoxy)piperidine D-tartrate (145 g). Chiral HPLC analysis indicated an enantiomeric ratio of 99.5:0.5 (Chiralpak AD-H, 4.6×250 mm, 5 μm, 210 nM, 0.2% isopropylamine-isopropanol, 0.7 mL/min; retention times 5.76 min (major enantiomer), 6.20 min (minor enantiomer). 1H NMR (400 MHz, DMSO-d6) δ 12.69 (br s, 1.5H), 9.34 (br s, 1H), 8.79 (br s, 1H), 7.12 (d, 1H), 7.03 (m, 2H), 6.89 (m, 1H), 5.09 (br s, 1.5H), 4.44 (m, 1H), 4.32 (s, 2H), 4.05 (q, 2H), 3.28 (m, 1H), 3.11 (m, 1H), 3.04 (m, 2H), 1.97 (m, 1H), 1.92 (m, 1H), 1.72 (m, 2H), 1.35 (s, 3H).

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